of the Fishery Board for Scotland 



223 



conditions of fresh-water lochs — as Loch Ness and Loch Morar, where the 

 water is of great depth, and where the shores dip rapidly, leaving very 

 little or no shallow margin — do not seem to favour the development of 

 the Ostracoda ; and it is interesting to compare in this respect the distri- 

 bution of the marine species of the same group, which extends from the 

 shore clown to many hundreds of fathoms. Another point of interest 

 maybe noted here, viz., though several species of Copepoda were obtained, 

 including one or two rare Harpactids, not a single Cantlwcamptus was 

 observed, — not even Cantlwcamptus minutus. Gammarus pulex — the 

 common fresh-water amphipod — was also conspicuous by its absence. 



Mollusca appeared to be very scarce : the only species observed were 

 Limncea peregra and Pisidium pusillum. 



LIST AND DESCRIPTION OF SPECIES. 



CRUSTACEA. 



COPEPODA. 



Family Calanid^e. 



Genus Diaptomus, Westwood. 



Diaptc/mus gracilis (G. O. Sars). 



1863. Diaptomus gracilis, G. 0. Sars, Oversigt af de indenlandske 



Eerskvands copepoder, p. 9. 

 1891. Diaptomus gracilis, Brady, Re vis. Brit. Cyclop, and Calan., 



p. 29, PL XII. figs. 7-9; PI. XII. figs. 1-8. 



Of common occurrence all over the loch, but comparatively few of the 

 specimens mature. 



Family Cyclopid/e. 

 Genus Cyclops, Muller. 



Cyclops viridis (Jurine). 



1820. Monocidus quadricornis viridis, Jurine ; Hist, de Monocles, 



p. 46, PI. III. fig. 1. 

 1891. Cyclops viridis, Brady, op. cit., p. 17, PL V. figs. 6-10. 



Common all over the loch. 



Cyclops serrulatus, Fischer. 



1851. Cyclops serrulatus, Fischer, Bull. Soc. Imp. Moscow, vol, 



xxiv. p. 423, t. x. figs. 22, 23, 26-31. 

 1891. Cyclops serrulatus, Brady, op. at., p. 18, PL VII. fig. 1. 



Frequent in bottom material collected at the head of the loch and at 

 Brinacory. 



Cyclops ewarti, Brady. (PL VI. figs. 1-10). 



1888. Cyclops ewarti, Brady, Sixth Annual Report of the Fishery 



Board for Scotland, Part lll. p. 232, PL VIII. figs. 1-10. 

 1891. C (/clops ewarti, Brady, Revis. Brit. Cyclop, and Calan., 

 p. 22, PL VII. figs. 4-7. 



length 1*8 mim (^f th of ail inch), StiCii frGhi tlife dorsal VieW, body 

 elongate, pynt'omi, tapering gradually to the abdomen first cepludo 



